Rotary switch



T. AMMANN.

ROTARY SWITCH.- I APPLICATION FlLED FEB- 19. 1918.

Patented Sept. 28,1920.

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ROTARY SWITCH.

Specification of Letters Patent. Pat t d S t 28 192 Application filed February 19, 1918. Serial No. 218,061. I

To all whom it may concern Be it known that I, THEOPHILE AMMANN, engineer, a citizen of the Swiss Confederation, and residing at Berne, Switzerland, have invented a certain new and useful Improved Rotary Switch, of which'the followingis a specification.

My invention relates to electric rotary switches. The known switches of this type having a dead left turn are provided with a special device adapted for that purpose. The parts of such a device must be exactly made, but they cannot be made very durable without looking clumsy and without becoming very complicated.

The object of my invention is to produce a switch having all the advantages of the old switches, while being constituted of but a few simple and strong parts and being therefore of great durability. A contact ring is pressed by means of well contact springs of known construction against an annular part having crown teeth and connected to the handle of the switch. The handle and insulating body are united to one and the same rotary body. The cen-- tral axis is secured by means of a conical seat-surface and the teeth on. the two faces of the contact ring are offset relative to each other.

Several embodiments of my invention are represented in the drawing by way of example.

Figure 1 shows a central section through one embodiment on line I-I of' Fig. 5; Fig. 2 is a lateral view of the rotary body with the contact ring. Fig. 3 is a top-view of the contact-ring and Fig. 4 aside view of the developed contact ring; Fig. 5 is a top view of the rotary switch with the outside casing removed and Fig. 6 a partial view-and a partial section on line VI-VI of Fig. 5 while Figs. 7 to 9 represent other embodiments.

The base member 1 (Figs. 1 and 5) has a circular socket 2 fitted with a central conical mound 3 whereof the apex is covered by a metal shield 4: serving as a seating surface for a rotary body '5 made of insulating material. The cylindrical part 6 of this rotary body 5 is shaped at its upper end like a handle 8 projecting from out the cap 7 and is provided at'its bottom end with an annular part 9. With its bottom face recessed at 10 and shaped to fit the mound 3 the rotary body 5 is seated centrally within the socket 2. The upper face ofthe annular part 9 is provided with 4 teeth and serves as a seating surface for a metal contact-ring 11. In order to secure without special means the central seating of this contact ring on the annular part 9 the seating surface is conically inclined. Ring 11 is provided on its bottom face with teeth corresponding with the tooth-intervals of the annular part 9 and on its top face with four teeth of the same inclination which in order to reduce the height of said ring are offset relative to the bottom teeth and whereof one tooth (in the simple switches there are two teeth) is covered with an insulating layer 12. Against each of these teeth bears with its free end a sliding contact spring, 13, 14, 15, 16 respectively (Fig. 5) pressing the contact-ring against its seat and the rotatable body 5 against its bearing surface 4. The contact springs lie with their fixed ends within a circular groove 17 arranged concentrically with the socket 2' so that they will be rigidly held by but one screw 18 shaped like a bind ing post. Two holes 19 are provided in the base member 1 for screws to fasten it' for instance to a wall.

The switch works as follows:

When the rotary body 5 is turned by means of the handle 8 ring 11 is taken along by the teeth of the annular part 9 whereby the insulated tooth 12 of the switch ring 11 will be brought at each quarter turn under one of the contact springs. If for instance in a switch provided with four con tact springs 13, 14, 15, 16 the conducting wire is attached at 13 the other contact springs 14:, 15, 16 will be without current. if 12 is located under 13. Therefore three current-consuming stations may be connected with such a switch. If used as a simple switch, only two contact springs will be needed, but the contact ring will then have two insulated teeth 12 located opposite each other. If therefore for instance only the two contact-springs 13 and 15 are provided, the two insulated teeth in the cut-out position will be located under 13 and 15; after a quarter right-turn the conducting portions of the contact ring will come to be located under 13 and 15 and the circuit-connection of the switch will become established.

If the switch-handle 8 be turned in an anti-clockwise direction the contact springs 13, 14, 15, 16 will prevent the contact-ring 11 from turning also. The teeth of the annular part 9 will then slide along under those of the ring and will lift the same against the action of the contact springs for a height twice that of a tooth. The dead-turn is thus rendered possible without special means.

While in the described embodiment the contact-ring 11 is pressed from above against the annular part 9 with its lower face, in the embodiment according to Figs. 7 to 9 it bears with its upper face against said annular part. The base member carrying the contact-springs is not shown here. The annular part 9 is beveled off on both of its faces and Will be pressed by the contact springs against a sliding-ring 20 which is resting against the conical inner face of the cap 21, so as to secure the central position of the rotary body within the opening of the cap. This cap is intended to project from the wall, while in Fig. 8 it is sunk within said Wall and is provided for this purpose With a covering plate 22. Utherwise this embodiment is the same as the one above described. According to Fig. 9 the rotary body is provided with a metallic square-sided axis 23 and does not protrude beyond the covering plate 22. The axis 23 with its cylindrical extension 24: fits into a central perforation of plate 22 and is provided with a metallic handle 25.

I claim as my invention:

1. An electric rotary switch having a dead left-turn comprising a base-member, a body of insulating material rotatably located in said base member and having an annular portion provided with cam teeth, a contact ring bearing on said annular portion and having in its bearing face corresponding cam teeth, and fixed contact springs adapted to engage projections provided in the other face of said contact ring and hold it pressed against said annular portion.

2. An electric rotary switch as set forth in claim 1, in which means are provided in said base-member and on the said rotary body for centering the latter within the socket of said base-member.

3. In an electric rotary switch as specified in claim 1, a contact ring made entirely of conducting material and provided on both faces with crown-teeth, one of said crownteeth being equipped with an insulating layer.

In testimony whereof I aflix my signature in the presence of two witnesses.

TH. AMMANN.

Witnesses: 4

lFRIEnERIoH N AEGELI, lFnrEnnRroH Momma. 

